Lesson 1: Basics for Understanding & Working with VFDs
Variable Frequency Drives; Becoming a Better Qualified Person when Working on VFDs; What is a Variable Frequency Drive; Basics for Understanding and Working with VFDs; Understanding Loads; Types of Torque; Other Load Considerations; Typical VFD Applications
– Describe how a VFD operates.
– Identify the components of a VFD.
– Recognize the various torque demands on a VFD.
– Name typical VFD applications.
Lesson 2: Motors for VFDs
Basics of Motors; Induction Motor Rotation Basics; Three-Phase Motor Operation; Motor Speed and Number of Poles; Volts/Hz Ratio; Motor Nameplate Information; Recommended Maximum Insulation Temperature; The Inverter Duty Rated Motor
– Explain the theory of AC motor operation.
– Understand the importance of Volts/Hz ratio.
– Describe the information on a motor nameplate.
– Recognize the importance of an inverter duty rated motor.
Lesson 3: VFD Data Input
Programming a VFD
– Identify the components on a VFD keypad.
– Enter Motor Nameplate Data into a VFD.
– View the VFD parameters on the keypad display.
Lesson 4: Measurement and Safety for VFDs
Safety and VFDs; Test Equipment for VFDs; Making Safe Measurements
– Identify OSHA safety standards.
– Use meters safely.
– Establish an electrical safe work condition.
– Choose the correct meter for troubleshooting VFDs.
Lesson 5: Hands-On Drive Exercises
Drive External Accessories; Drive Exercises
– Review a schematic diagram for external VFD accessories.
– Connect indicator lights to an internal drive relay.
– Connect inputs for various desired control functions.
– Check the fault code register to determine the history of faults.
Lesson 6: Electronics for VFDs
3-Phase Rectification: The VFD “Front End”; Values Along the Sine Wave; The Diode Symbol; Checking Solid State Components in the Field; Full-Wave Bridge Rectifier; Ripple Voltage and Filtering; Types of Drives
– Understand how an AC sine wave is generated.
– Explain the process of rectification.
– Identify semiconductor components.
– Describe pulse width modulation.
– Recognize basic drive types.
Lesson 7: Sizing and Selecting VFDs
Steps for Selecting a VFD; Sizing and Selecting VFDs; Key VFD Specs; Special Considerations
– Create an equipment profile.
– Prepare a detailed analysis of performance requirements.
– Research either machine or process equipment history.
– Identify environmental conditions.
– Analyze the power distribution system.
Lesson 8: Installation and Startup of VFDs
Steps to Selecting a VFD; VFD Installation Requirements; Startup
– Develop a checklist of items.
– Comply with manufacturer’s instructions and specifications.
– Identify with National Electrical Code® requirements.
– Verify proper overcurrent protection to drive.
Lesson 9: Troubleshooting VFD Systems and Motors
Troubleshooting 3 Phase Motors; Insulation Considerations for VFD Motors; Solutions Used to Prevent Motor Failures; Motor Bearing Issues for VFDs; Bearings; Resolving Bearing Problems; Troubleshooting VFDs; VFD Faults;
– Troubleshoot three-phase motors.
– Identify motor failures.
– Discuss the six conditions needed to troubleshoot VFDs.
– Discuss a by-pass option.
Lesson 10: Preventative Maintenance
Preventive Maintenance: NETA Recommendations
– Conduct a visual and mechanical inspection of the VFD.
– Perform electrical testing.
– Test the equipment grounding path.